Brake mechanism



sept. 17, 1940. R J. BUSH 2,215,346

` BRAKE MECHANISM Filed July 26, 1939 lNvENToR/ HANKIN d, BUSH ATTORNEYPatented Sept. 147, 1940 l UNis y sir man@ BRAKE MECHANISM Ranl'rin J.Bush, Jeanette, Pa., assigner to The "WestinghouseAir Brake Company,Wilmerding,

Pa., a corporation of Pennsylvania Application .any 26, 1939, seriaino.285,597

i1 claims.

This invention relates tobrake mechanism for railway Vehicle trucks andmore particularly to brake mechanism of the type disclosed in anapplication of Carlton D. Stewart Serial No. 214,517,

:'x; filed June 18, 1938, (Case 4480), in which there is employed clasparranged brake elements operative into braking engagement with a brakingsurface which is rotatable with one of the Wheel and axle assemblies ofthe truck, which clasp arrangedbrake elements and mechanism foractuating them are carried by a brake carrier Which is mounted ,on theframe of the truck for vertical movement relative thereto, and whichcarries a third brake element for engagement with the braking surfaceupon movement of the carrier by the clasp arranged elements.

In the apparatus shown and described in the aforementioned Stewartapplication each brake carrier extends over the top of va brakingsurface 2Q- on the wheel and axle assembly. In some railway vehicleconstruction, the clearance directly above the braking surface,especially when the braking surface is the track rail engaging surfaceof the tread portion of the Wheel, may be so limited as to preclude theuse of the carrier in this position,4and with this in mind, theprincipal object ofthe invention is to provide a brake mechanism of theabove type having the brake carrier so constructed and arranged as torequire minimum clearance above the braking surface of the wheel andaxle assembly, thereby eliminating the clearance difculties hereinbe-Vfore mentioned.

Another object of the invention is to provide 'f a brake mechanism ofthe above mentioned type having the brake carrier so constructed andarranged with relation to the wheel and axle assembly that it willrequire no more clearance above the braking surface of the assembly thanthat required by the brake element which it carries and which it isadapted to move into engagement with the braking surface.

Another object of the invention is to provide a novel brake mechanism ofthe above mentioned a type which is especially adapted for frictionalbraking engagement with track rail engaging surface of the tread portionof one of the wheels of a wheel and axle assembly of the truck.

Other objects and advantages will appear 1n thefollowing more detaileddescription of the invention.

In the accompanying drawing Fig. 1 is a plan View of a portion of oneend of a railway vehicle 55 truckembodying the. invention; Fig. 2 isa'longitudinal sectional View taken onthe line 2-2 of Fig. lto show themechanism in side elevation, portions of the mechanism being broken awayto more clearly illustrate certain details of construction; and Fig. 3is a cross sectional view taken on the line,3-3 of Fig. 2, the truckframe being omitted.

For illustrative purposes only, the invention is shown in conjunctionwith a railway vehicle truck of the conventional type comprising a castmetal vtruck frame having laterally spaced lon-A, gitudinally extendingside pieces I which are integrally connected together at each end by an,end piece 2 and are integrally connected intermediate their ends by theusual spaced parallel extending transoms 3; the truck also comprises aplurality of Wheel and axle assemblies eachy of which compriseslaterally spaced wheels i Which are connected together transversely ofthe truck byY an axle 5, which axle, at each side of the truck may bejournaled in an axle box 5 mounted between the usual spaced pedestaljaws 'I depending from a side piece of the truck frame. The truck frameis movable vertically relativeto. the wheel and axle assembly and isresiliently carried by the Wheel and axle assemblies through the mediumof springs 8each of which springs,

in the present embodiment of the invention,-l

rests on the upper surface of an axle box 6. j

The brake mechanism may be complete Afor asy many individual wheels ofthe truck as desired, and has been shown in conjunction withonly onewheel of a wheel and axle assembly andthe adjacent portions of one' endof the truck frame, and for the sake of simplicity the following de-Scriptum win be more or less umited towhat is shown.

The track engaging surface of the tread portion of the Wheel 4 isadapted to be frictionally engaged by brake elements I0, II and i2 whichare radially arranged about the Wheel, the elements I0 yand lI beinglocated at opposite sides of the wheel andthe element I2 being locatedabove the wheel. The greater portions of the elements I0 and" I I extendbelow the horizontal center line of the wheel while theelement I2 iscentered on substantially the vertical center line of the wheel. It willhereV be understood thatl each brake element may comprise the usualbrake shoe and brake shoe head, but since this construction of head andshoe is so well known, each element will, for simplification, beherein-` after referred to as a brake shoe.

Located at the inner side of the side piece I alc of the truck frame andextending longitudinally thereof is a combined lever and brake carriermember i3 which, in the present embodiment of the invention, is of yokeform having laterally spaced parallel side pieces I4 arranged one oneach side of the wheel 4 and below the top of the track engaging surfaceof the tread portion of the wheel. The inner ends of these side piecesI4 are pivotally connected, by means of a pin I5, to laterally spacedlugs i6 for vertical movement relative to the truck frame, which lugsextend outwardly from the transom 3 in a direc-V tion toward the-wheel.At the outer ends of the member the side pieces are connected togetherby an end piece II having an outwardly extending lug I8 which extendsinto a hollow casing I9 secured to the end piece 2 of the truck frame.The under surface of this lug rests on a spring seat 2B which issupported by a release spring 2I seated on the bottom wall of thecasing.

Extending through a central opening in the spring seat 23 and bottomwall oi the casingis a bolt`22 having at its upper end a head 23 whichis square in cross section 'and which is accommodated by acorrespondingly shaped opening provided in the lug I8. The under side ofthe head of this bolt engages the spring seat, and since, as shown, thelower end` of the bolt is provided with a nut 24 which engages the lowersurface of the bottom wall of the casing, the head of the bolt willlimit upward movement ofthe spring seat 20 relative to the `truck frame.The nut is rotatable toefect any desired adjustment of the boltvertically relative to the truck frame and this nut is held againstaccidental rotation on the bolt by means of a check nut 25.

Interposed between and operatively engaging the upper side of the lug`I8 and the top wall 2B of the casing I9 is a spring 2'I'which isadaptedy to resist accidental upward movement of .the outer end of themember I3 `when the member is in its normal release position as bestshown in Fig. 2. This spring 2'! also serves to prevent the dead weightof the truck frame carried thereby from being transmitted to the memberI3, when, with the brakes applied, the truck frame for any reason movesdownwardly relative to the wheel and axle assembly.

At 'one'side of the wheel there is provided laterally spaced hangerlevers 30 and 3l, which in the present embodiment oi the invention areeach of modified bell crank form having arms 32 and 33 which aredisposed at an angle to each other, the upper end of the arm 32 of thelever 39 ispivotally hung from one of the side pieces i4 of the memberI3 by means of a transversely extending pin 34, and the upper end of thecorresponding arm of thevlever 3l is pivotally connected in the samemannerto the other side piece I4 of the member. rlhe brake shoe I0 has aportion which extends between the lower ends of the arms 33 of thelevers 3U and 3| and is pivotally supported from these arms by means ofa transversely extending pin 35 which is mounted in the arms.

A lso extending between the levers 30 and 3l and pivotally carriedthereby through the medium cfa Ytransversely extending pin 36 is a liveor brake cylinder lever '31, the pin`35 passing through the levers at apoint intermediate Vtheir ends.

The upper` end ofY the lever 3`I is operatively connected to the outerend of `apush rod 38 of a brake cylinder device 39 which is rigidlysecured to the outer end portion of the member I3.

The brake cylinder device may be of the usual construction having apiston 40 which is operative to actuate the push rod 38, and having arelease spring 4I interposed between and operatively engaging the pistonand the non-pressure head of the brake cylinder casing. At one side ofthe piston is a pressure chamber 42 which is in communication with aiiexible conduit 43 through which fluid under pressure may be admittedand released from the chamber 42 for controlling the operation of thebrake cylinder piston.

The lower end of the brake cylinder lever is operatively connected tothe adjacent ends of laterally spaced longitudinally extending con- 30and iand which may be supported fromtheV member I3 in the same manner.The levers 46 and 4I are operatively connected to the brake f shoe II inthe same manner as the levers 30 and- 3I are connected to the brake shoeI0.

The upper end of the dead lever 45 is pivotally Also carried by the'sidepieces I4 and extending upwardly therefrom are laterally spaced lugs 52which, at their upper ends have operatively' connected thereto, by meansof transversely extending pins 53, the brake shoe I2.v

By interposing the hanger levers between the brake levers 37 and '45,such levers 31 and 45 are made shorter than would be possible if theywere directly connected to the brake shoes. This makes it possible tomount the brake cylinder on the brake carrier I3 and to also locate thtconnecting bars 44 well above the track rails where theyaare not liableto be damaged. With the brake cylinder device k39 devoid of fluid underpressure the brake rigging will be in release position as shown in thedrawing and will be maintained in this position by the force of gravityor by a release spring when such a spring is employed. In this `positionthe weight of the brake rigging which is transmitted to the outer end ofthe member I3 will be insuflicient to compress the spring 2| and fromthis it will be apparent that when the brake rigging is in releaseposition this spring will maintain the member in lits normal position asshown.

Application of the brakes When it is desired to effect an application'ofthe brakes, fluid under pressure is admitted in the usual manner to thebrake cylinder pressure chamber 42 by way of the exible conduit 43. Inresponse to the pressure of iiuid thus admitted, the brake cylinderpiston 40 Yfunctions to actuate the push rod 38 and thereby the brakecylinder levers`3'I and hanger levers 30 and 3| and 46 and/41 to causethe brake'shoes I0 and II to frictionally engage the track engaging.lsurface of the tread portion of the wheel 4. With the brake shoes I0 andII in such engagement, the increasing force applied to the brake' shoesthrough the operation of the brakecylinder de- 45. outer end portion ofthe member I3'through the the rail engaging surface of the wheel. YThisdownward movement is due to the location of'the shoes below thehorizontal center line of the brake drum and to the application of thebraking force to the shoes in a direction substantially parallel to thehorizontal center line of the wheel and axle assembly. The downwardlyVdirected force, ue to such action being transmitted through the hangerlevers 3U, 3l, 46 and Il causes the member to move downwardly about thepin l5 and against vthe opposingaction of the spring 2l until such timeas the brake shoe I2 engages the wheel. At this time downward movementof the member I3 and the brake rigging will stop since the lmember willnow be supported by both the truck frame andthe wheel IL With the wheeland axle assembly rotating in the direction indicated by the arrow inFig, 2, the drag of the wheel 4 on the brake shoel IU at the front endof the truck will cause a further downwardly directed pull to be appliedto the hanger levers 30 and 3I and thereby to thel outer 'end portion ofthe associated member I3, thus augmenting the force applied to the brakeshoe I2. The drag of the wheel on the brake shoe Il at this end of thetruck has a tendency to move `the shoe upwardly, but this tendency isoverbalanced by the downward force set up by shoes as they tend to movedownwardly along the braking surface on the wheel under the influence ofbrake cylinder pressure appliedv to the lever In other words, the forceapplied to the medium of the hanger levers 39 and 3l is the sum of thedownwardly directed force produced by the action of the shoe lli underthe influence of brake cylinder pressure and the force produced by thedownward drag of the wheel on the shoe. while the force applied to themember 'I3 through the medium of the hangers i6 and 4l is that producedby the action of the shoe II'underV the inuence of brake cylinderpressure minus the force due to the upward drag of the wheel on theshoe. From this it will be apparent that the downward pull of the brakeshoe4 I0 at the leading side of the wheel will exceed the downward pullof the brake shoe at the other side of the wheel. At the other or rearend of the truck the downward pull. of the brake shoes I and II on themember I3 is just the reverse of that of the shoes at the front end ofthe truck since the dis- ,V position of the shoes with respect to theleading and other side of the brake drum isthe reverse of that at thefront end.

It will here be noted that at the front end of the truck the greaterpull of the brake shoe at the leading side of the wheel 4 is transmittedto the outer end of the member I3 while at the rear end of the truck thecorresponding pull of the brake shoe at the leading side is applied tothe member I3 intermediate its end. As a result the brake shoe I0 at thefront end of the truck will be applied with greater force to the wheelthan will the corresponding brake shoe at the rear end of the truck.

`It will be evident that with the brakes applied the members l 3 willtend to rotate with the wheel 4 so that the member at the front end ofthe truck will exert an upward force Von its pivot pin `I5 and themember at the rear end of the truck will exert a downward force on itspivot pin.

i It will be seen that with the brake rigging in application position,the -brake shoecIZ, besides servingto assist -in supporting the. memberI3' and thereby the brake rigging, also acts to resist rotary movementof the wheel and axle assembly, thus materially increasing the brakingaction on the-assembly for any given brake applying force applied to therigging. v y f When the vehicle is in inotion and an application of thebrakes is initiated, the momentum of the body of-the vehicle has a'tendency to tilt the truck forwardly with the result that the adhesionbetween vthe reartruck wheels and the track rails will lbeunintentionally increased so that these wheels will have a greatertendency to slide on the rails than will the front truckwheels.

With this inmind the brake arrangement disclosed in the drawing has beenso designed that the'total braking force of the three brake shoes on therear wheelsof the truck for a given brakeV When it is desired to releasethe brakes, fluid under pressurev is vented from the brake cylinder.chamber d2 by way of the flexible conduit i3 and when this isaccomplished the usual release spring dil,- in the brake cylinder devicecauses the brake cylinder piston it and push rod 38 to move inwardly totheir normal release position. At the same time the iorce of gravitycauses the brake lshoes ill and II and the several parts of the brakerigging asscciatedtherewith to assume theirnormal release-positions asshown in `the drawing. It will here be noted that las the brakes shoes'lil and II move out of contact with the wheel 4l the spring 22 acts toraise the outer end of the member lfthereby moving the brake shoe I2 outof engagement with the wheel, the` Modifications in the structureillustrated andy described may be made without departing from the spiritof my invention, and I do not therefore wishV to be limited otherwisethan by the scope of the appended claims.

Having now described my invention, what'VI claim asA new' and desire tosecure by Letters Patent, is: v l

`1. In a brake' mechanism for a railway vehicle truck, in combination,awheel and axle assembly having a braking surface, clasp arranged brakeelements movable into braking engagementwith said surface, braking meansalso movable into braking engagement with said surface, hanger leversfor supporting s aid clasp arranged brake elements from said brakingmeans and operable to actuate said elements, and operatively connectedlive and dead levers operative for actuating said han-ger levers, saidclasp arranged brake elements when in engagement with said surfaceacting through' the medium of the hanger levers for actuating saidbraking means. Y

y2. In al brake mechanismy for a railway vehicle truck, in combination,a wheel and axle assembly having a braking surface, clasp arranged brakeclasp brake elements, braking means also movable into braking engagementwith said surface,

auf

and operatively connected dead and live levers for actu-ating saidhangerV levers, said hanger` levers being supported by said brakingmeans and being operable by the clasp arranged brake elements foractuating the braking means. 3. In a 'brake mechanism for a railwayvehicle truck, in combination, a wheel and axle assemblyv having abraking surface, clasp arranged brake elements movable into brakingengagement with said surface, braking means also movable into brakingengagement with said surface, hanger levers for supporting said clasparranged br-ake elements from said braking means and operable to actuatesaid elements, and operatively connected live and dead levers carried bysaid hanger levers and operative for actuating the hanger levers, saidclasp arranged brake elements when moved into engagement with saidsurface acting v through the medium of the hanger levers for actuatingsaid braking means.

t 4. In a brake mechanism for a railway vehicle truck, in combination, awheel and axle assembly having a braking surface, clasp arranged brakeelements movable into braking engagement with said surface, brakingmeans also movable into braking engagement with said surface, hangerlevers for supporting said clasp -arranged brake elements from saidbraking means and operable to actuate said elements and operativelyconnected live and dead levers carried by said hanger levers andoperative for actuating said hanger levers, said clasp arranged brakeelements when moved into engagement with said surface acting through themedium of Said hanger levers for actuating said braking means, and saiddead lever being adjustably fulcrumed to said braking means to permitfree relative vertical movement between the lever and braking means. v

5. The combination with a railway vehicle truck comprising a wheel andaxle assembly and a truck frame supported by said assembly, of brakemeans movable into braking engagement with said assembly, said brakingmeans comprising two brake shoes disposed in clasp arrangement aboutsaid wheel and axle assembly and movable into braking engagement withthe assembly, a hanger lever supporting'each of the clasp arranged brakeshoes and operable to actuate said shoe, operatively connected leverscarried by the hanger levers and operative to actuate the hanger levers,another brake shoe movable into engagement with said assembly, and meansfor actuating said other brake shoe, said means being adapted to supportsaid hanger levers and being operable bythe hanger levers to move saidother brake shoe into braking engagement with said assembly.

6. The combination with a railway vehicle truck comprising a wheel andaxle assembly and a truck frame supported by said assembly, of brakingmeans movable into braking engagement with said assembly, said brakingmeans comprising two brake shoes disposed m clasp arrangement about saidwheel and axle assembly and movable into braking engagement with theassembly, a hanger lever supporting each of the said shoes and operableto actuate the shoe, operatively connected dead and live levers carriedby the hanger levers and operative to actuate the4 hanger levers,another brake shoe movable into engagement with said assembly, means foractuating said other brake shoe, said means being adapted to supportsaid hanger levers andbeing operable by the hanger levers tomove saidother brake shoe into braking engagement with saidassembly, and a brakecylinder device carried by Asaid means operative to actuate said livelever.

7. The combination with a railway vehicle truck comprising a truck frameand a supporting wheel and axle assembly, of a clasp brakemechanismoperative into braking engagement with the track rail engagingsurface of one of the wheels of said assembly, said brake mechanismbeing movable downwardly relative to the truck frame when in engagementwith said surface inresponse to the forces set up due to the brakingaction between said mechanismand surface, a support member fo-r saidclasp brake mechanism located below the topV of said surface and movabledownwardly relative to the truck frame by the clasp brake mechanism whenthe clasp brake mechanism moves downwardly, a combined brake and supportelement adapted to be moved by said support member into contact with thetop of said surface, and means for operatively connecting said`elementand support member.

8. The combination with a railway vehicle truckcomprising a truck frameand a supporting wheel and axle assembly, of a clasp brake mechanismoperativeV into braking engagement with the track rail engaging surfaceof one of the wheels of said assembly, said brake mechanism being movedVdownwardly relative to the truck frame when in engagement with saidsurface in response to theforces set up due to the braking action'between the mechanism and surface, a support member for said clasp brakemechanism located below 'the top of said surface and movable downwardlyrelative to the truck frame by the clasp brake mechanism when the claspbrake mechanism moves downwardly, a combined brake and support elementadapted to be moved by said support member into contact with the top ofsaid surface, and means carried by and extending upwardly from saidsupport member operatively connected to said element.

9.' The combination with a railway vehicle truck comprising a truckframe and a supporting wheel and axle assembly, of a clasp brakemechanism operative into braking engagement with the track' railengaging surface of one of the wheelsl of said assembly, said brakemechanism being movable downwardly relative to the truck frame when inengagement with said surface in response to the forces set up due to thebraking action between said mechanism and surface, a support member forsaid clasp brake mechanism located below the, top of said surface, andmovable downwardlyrelative to the truck frame by the clasp brakemechanism when the clasp brake mechanism moves downwardly a combinedbrake and support element adapted to beV moved by said supportmemberinto contact with the top of said surface, and a lug carried by andextending upwardly from saidsupport member, and means operativelyconnecting said element to said lug.-

10. The combination with a railway vehicle truck comprising a truckframe and a supporting wheel and axle assembly, having a brakingsurface', a clasp brake mechanism operative into braking engagement withsaid surface, said brake mechanism being movable downwardly when .inbraking engagement with the surface in response to the forces set up dueto the braking action between the mechanism and surface, a supportmember for said clasp brake mechanism carried by said truck frame andmovable downwardly relative to the truck frame4 by the clasp brakemechanism when the mechanism moves downwardly and means movable by saidsupport member into engagement with said surface, said support memberbeing located below said means and having an upwardly extendingprojection operatively connected to said means.

11. The combination with a railway vehicle truck comprising a truckframe and a supporting wheel and axle assembly, having a brakingsurface, a clasp brake mechanism operative into braking engagement withsaid surface, said brake mechanism being movable downwardly when inbraking engagementI with the surface in response to the forces set dueto the braking action between the mechanism and surface, a supportstructure for said clasp brake mechanism carried by said truck frame andmovable downwardly relative to the truck frame by the clasp brakemechanism when the mechanism moves downwardly, and means movable by saidsupport structure into engagement with said surface, said supportstructure comprising a pair of longitudinally extending laterally spacedside pieces located below said means and arranged one at each side ofthe wheel and having upwardly extending projections operativelyconnected to said means.

RANKIN J. BUSH.

